import java.util.*;


public class code2 {
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     *
     * @param board string字符串一维数组 
     * @param word string字符串 
     * @return bool布尔型
     */

    int m,n;
    int[] dx = {0,0,1,-1};
    int[] dy = {1,-1,0,0};
    boolean[][] vis;
    char[] word;
    public boolean exist (String[] board, String words) {
        m = board.length;
        n=board[0].length();
        vis = new boolean[m][n];
        word = words.toCharArray();
        for(int i=0;i<m;i++) {
            for(int j=0;j<n;j++) {
                if(board[i].charAt(j)==word[0]) {
                    if(dfs(board,i,j,0)) return true;
                }
            }
        }
        return false;
    }
    public boolean dfs(String[] board,int i,int j,int pos) {
        //递归出口
        if(pos==word.length-1) return true;
        vis[i][j] = true;//标记
        for(int k=0;k<4;k++) {
            int x =i+dx[k];
            int y =j+dy[k];
            if(x>=0&&x<m&&y>=0&&y<n&&!vis[x][y]&&board[x].charAt(y)==word[pos+1]) {
                if(dfs(board,x,y,pos+1)) return true;
            }
        }
        vis[i][j] = false;//恢复现场
        return false;
    }
}